President's Address. 9 



" List of some of the Silurian Fossils of Ayrshire," * appended 

 to Murchison's memoir, " On the Silurian Itocks of the South 



of Scotland." t 



About, and previous to tlie year 1850, Murchison had 

 traversed the larger portion of the area in question, accom- 

 panied by Professor J. Nicol. Around Girvan his researches 

 were assisted by the local knowledge of Alexander Maccallum, 

 a resident, who combined the avocation of a weaver with the 

 pastime of fossil collecting. A friend, who knew the neigh- 

 bourhood of Girvan well in these early days, has afforded me 

 the following; information about Maccallum : — He was the 

 first person who collected in the neighbourhood, and often 

 laid aside his work to gratify his liking for rambling over 

 the country in search of curiosities. After he became known 

 he acted as guide to geologists visiting Girvan, and in this 

 capacity became acquainted with Sedgwick, Murchison, and 

 Hugh Miller, He was, besides a weaver and fossil collector, 

 a fiddler at country dances. He died in 1854, aged fifty-one. 

 Maccallum managed to gather a goodly number of fossils, the 

 majority of which were shells. These, after due comparison 

 with kindred collections from Wales, were determined by 

 Salter, to the number of thirty-seven species. The evidence 

 aftbrded principally by these fossils enabled Sir Eoderick 

 Murchison to lay down the first rough classification of the 

 Silurian rocks of Girvan. Glancing at the list, the first im- 

 portant point which strikes us is the general absence of 

 Mollusca of truly Upper Silurian age, and the prevalence of 

 forms of a decidedly Middle Silurian type. The 37 species 

 comprised 17 Brachiopods, 1 Bivalve, 13 Univalves, and 6 

 Cephalopods, or chambered shells. 



We observe, for the first time in palcTontological annals, 

 the record of that characteristic and important Llandovery 

 shell Pentameriis, in the conglomerate of Cuddystone Glen, 

 and the shelly sandstone of Mulloch Hill. Amongst the other 

 Brachiopods which may be referred to as interesting are a 

 Terebratula,X ^^ ^^^^ Craighead limestone, probably identical 

 with a Canadian species ; another American form, Orhkula 



■" Quart. Jour. Geol. Soc, vii., pi*. 170-178. f ////(/., ].]). 139-169. 



t Probably a Meristclla. 



